textproduct: Rapid City
This forecast discussion was created in the public domain by the National Weather Service. It can be found in its original form here.
KEY MESSAGES
- Showers and storms continue into the overnight hours.
- More chances for afternoon storms on Wednesday, mainly across western SD.
- Trending warmer to end the week into next weekend.
UPDATE
Issued at 1016 PM MDT Tue Aug 18 2026
Current radar has widespread showers/storms over the forecast area this evening, with some wind gusts near 50 mph around storms. Precipitation will continue overnight, moving out from west to east early Wednesday morning.
Forecast remains mostly on track. Have removed PoP mention during the day Wednesday. Models are all pointing to us being dry, and CAMs show nothing during the afternoon/evening. It's not impossible, but more likely most places will remain dry once the overnight showers/storms move out. Things then look mostly dry the remainder of the week as ridge dominates the northern plains. Next significant disturbance looks to move through the area Sunday.
DISCUSSION
(This Evening Through Tuesday) Issued at 1242 PM MDT Tue Aug 18 2026
Shortwave will push through region today and bring another round of storms to the CWA this afternoon. Modestly unstable airmass of 1500- 2000 J/kg MUCAPE will develop over western SD by this afternoon and evening. The instability combined with 40-50kt bulk shear will support organized convection and potential severe weather. Main hazards will be strong wind gusts (some gusts could exceed 70 mph) and large hail. There is still uncertainty as to the timing and coverage of convection this afternoon, though right now it looks like the most likely area for severe storms stretches from northeastern WY into portions of western and south central SD.
Wednesday is looking drier as rising heights courtesy of the building ridge to our west will limit convection. We could still see some isolated storms towards the eastern third of our CWA where 1000- 1500 J/kg MUCAPE will develop by the afternoon.
The upper level pattern shifts after Wednesday as aforementioned ridge continues to build over the western US and overspreads the region. Our CWA will sit on the northeastern periphery of the ridge, meaning we'll see warmer temps and continued chances for storms through the end of the week.
AVIATION
(For the 12Z TAFS Through 12Z Thursday Morning) Issued At 452 AM MDT Wed Aug 19 2026
Storms will end in scentral SD this morning. Otherwise, VFR conds in the period all places.
UNR WATCHES/WARNINGS/ADVISORIES
SD...None. WY...None.
IMPORTANT This is an independent project and has no affiliation with the National Weather Service or any other agency. Do not rely on this website for emergency or critical information: please visit weather.gov for the most accurate and up-to-date information available.
textproduct.us is built and maintained by Joshua Thayer.